1. Field of the Invention
This invention relates to a motor driven seat apparatus used for an automobile, for example, and more particularly to a power seat apparatus which is possible to adjust a seat automatically in suitable positions, heights and reclining angles of the seat backs memorized in a memory means for respective drivers individualy.
2. Description of the Prior Art
Heretofore, there has been used a power seat apparatus as shown in FIG. 7, for example.
Namely, the power seat apparatus is provided with a slide-motor for sliding a seat in a front or rear direction, a lift-motor for driving the seat up or down, and a recliner-motor for adjusting a reclining angle of a seat back of the seat, the slide-motor part is only shown in FIG. 7 among the aforementioned motors.
A power terminal 101a of the slide-motor 101 is connected with a travelling contact rl.sub.1-1 of a relay RL.sub.1, and a normal-close side fixed contact rl.sub.1-2 of the relay RL.sub.1 is connected with a power source 50 and a relay coil rl.sub.1 of the relay RL.sub.1.
The relay coil rl.sub.1 of the relay RL.sub.1 is connected to a fixed contact SW.sub.1-2 of a front-side manual switch SW.sub.1 having a movable contact SW.sub.1-1 grounded, and connected to a port 102a of a controller 102 and to the collector of a transistor Tr.sub.1.
A normal-open side fixed contact rl.sub.1-3 of the relay RL.sub.1 and the emitter of the transistor Tr.sub.1 are grounded and the base of the transistor Tr.sub.1 is connected to the port 102b of the controller 102.
Another power terminal 101b of the slide-motor 101 is connected to a travelling contact rl.sub.2-1 of a relay RL.sub.2, and a normal-close side fixed contact rl.sub.2-2 of the relay RL.sub.2 is connected to the power source 50 and a relay coil rl.sub.2 of the relay RL.sub.2.
Furthermore, the relay coil rl.sub.2 of the relay RL.sub.2 is connected to a fixed contact SW.sub.2-2 of a rear-side manual switch SW.sub.2 having a grounded movable contact SW.sub.2-1, and connected to a port 102c of the controller 102 and the collector of a transistor TR.sub.2.
A normal-open side fixed contact rl.sub.2-3 of the relay RL.sub.3 and the emitter of the transister Tr.sub.2 are grounded, and the base of the transister Tr.sub.2 is connected to a port 102d of the controller 102.
The controller 102 is provided with a microcomputer in which signals are input from a switch board (not shown) through an interface circuit.
In a case of memorizing a seat position suitable for a driver, the switch board is operated preparatively in the first place. Subsequently, the slide-motor 101 is driven in the front or rear direction by operating the front-side manual switch SW.sub.1 or the rear side manual switch SW.sub.2 and stopped at the seat position suitable for the driver.
By the setting operation of the switch board in this state, the microcomputer detects the positional displacement by counting the number of rotations (pulses) of the slide-motor 101 until the seat arrives at the present position, and the seat position is memorized according to the number of rotations of the slide-motor 101.
After this, it is possible to drive the slide-motor 101 automatically by the one-touch operation of the switch board until the seat arrives to the seat position memorized by the microcomputer wherever the seat may be.
If the front-side manual switch SW.sub.1 or the rear-side manual switch SW.sub.2 is changed on when the slide-motor 101 is driven automatically according to the data memorized in the microcomputer, output from the microcomputer to the slide-motor 101 is discontinued and output from the aforementioned manual switch SW.sub.1 or SW.sub.2 is given priority to the output from the microcomputer.
In the conventional power seat apparatus described above, in a case where the rear-side manual switch SW.sub.2, happens to be switched on for some reason when the slide-motor 101 is driven automatically in the front direction toward the position memorized by the microcomputer, for example, both power terminals 101a and 101b of the slide-motor 101 are grounded, so that the motor 101 is stopped by the dynamic braking, but rotates slightly by inertia after the dynamic braking.
At this time, the controller 102 judges the slide-motor 101 to rotate in the rear direction incorrectly in spite of the fact that the slide-motor 101 rotates in the front direction by inertia at the same time of changing on the rear-side manual switch SW.sub.2 because the controller 102 detects the number of rotations of the slide-motor 101 by the pulse transformation and the judgement of the rotational direction of the slide-motor 101 is done on basis of the detection.
Accordingly, there is a discrepancy between the seat position and the memorized number of rotations of the slide-motor 101 because the controller 102 counts the number of rotations while the slide-motor 101 rotates by inertia as a pulse in the opposite direction. Therefore, there is a problem since it is not possible to drive the seat properly to the position memorized suitably for the driver.
Furthermore, in the conventional power seat apparatus, if a contact fault occurs in the relay RL.sub.1 and the manual-open side fixed contact rl.sub.1-3 sticks fusingly to the movable contact rl.sub.1-1, for example, the slide-motor 101 is driven in the front direction in spite of off-operation of the front-side manual switch SW.sub.1. In such a case, it is possible to stop temporarily the slide-motor 101 by on-operation of the rear-side manual switch SW.sub.2 so as to cut off the power supply to the slide-motor 101, but the slide-motor 101 rotates again in the front direction by discontinuing the on-operation of the rear-side manual switch SW.sub.2. Therefore, there is another problem since abnormality in the apparatus can not be recognized by the driver until the seat is driven by the slide-motor 101.